Gunmen murdered 16 people in the retirement home in Yemen on 4 March. Sister Sally said he is 'so sad' that she did not die with her sisters but believes 'God wanted a witness' to the massacreSaleh Al-Obeidi/AFP/Getty

The sole survivor of an Islamic State (Isis) massacre of nuns by gunmen in an retirement home in Yemen has provided a first-hand account of the killings. Four Catholic nuns and 12 other people were killed on 4 March when gunmen stormed the retirement home run by a charity established by Mother Teresa.

Sister Sally, the superior of the Missionaries of Charity, survived the attack and has now given her account of the massacre. Her description was recorded by another Missionary of Charity, Sister Adriana, and copies of the handwritten account were published on the Catholic news website, aleteia.org.

The report began: "Isis dressed in blue came in, killed guard and driver. Five young Ethiopian men (Christian) began running to tell the Sisters Isis was here to kill them. They were killed one by one. They tied them to trees, shot them in the head and smashed their heads."

The account goes on to describe now the nuns ran in different directions and others screamed, "Don't kill the Sisters". It notes that when the sisters began to run, Sister Sally ran to the convent to attempt to warn Father Tom.

The nun reportedly saw "all the sisters and helpers killed" in front of her and saw gunmen heading towards the convent. She was forced to hide in the refrigerator room while Islamic State (Isis/Daesh) gunmen were "everywhere searching for her" as she believed that they knew there were five nuns.

The account states: "At least three times they (gunmen) came into the refrigerator room. She did not hide but remained standing behind the door – they never saw her. This is miraculous."

According to the detailed account, IS gunmen stormed the retirement home at 8.30am and only left between 10am and 10.15am. Religious articles were "smashed and destroyed", including the crucifix, prayer books and the Bible.

In the account, it is revealed that Sister Sally is "so sad" as she is alone and did not die with her sisters. However, the nun notes that "God wanted a witness" to the massacre and that if she had not been there to tell the truth about what happened, she is not sure who would have found the bodies of the nuns and what they would have told the world.

While no one has claimed responsibility for the attack, Sister Sally's description referred to them as "Isis" terrorists and Yemeni officials also placed blame on IS.